CA1069716A

CA1069716A - Universal joint and cross therefor

Info

Publication number: CA1069716A
Application number: CA275,623A
Authority: CA
Inventors: John C. Mcelwain; Lawrence H. Hogan
Original assignee: Rockwell International Corp
Current assignee: Boeing North American Inc
Priority date: 1976-05-13
Filing date: 1977-04-05
Publication date: 1980-01-15
Also published as: FR2351312B1; IT1081744B; SE432294B; DE2721706A1; AU2433777A; US4047396A; BR7703078A; FR2351312A1; US4103512A; GB1571337A; AU513543B2; SE7705555L

Abstract

UNIVERSAL JOINT AND CROSS THEREFOR

Abstract of the Disclosure A universal joint includes a cross operably connected therein, the cross comprises a body having four trunions extending therefrom along two mutually perpendicular lines, a lubrication network in the body and the trunions to provide lubrication to the cylindrical outer bearing surface of the trunions, the network includes a plurality of branches in communication with and terminating in a counterbore provided internally in each of the trunions, each counterbore having a cylindrical inner surface coaxial with the cylindrical outer bearing surface of the trunions, the counterbore is open at its end opposite the branches, a flow metering member having at least one metering orifice therethrough fixedly disposed within each of the counterbores to meter lubricant flowing from each of the branches downstream into the counterbore and to the bearing means and various bearing surfaces associated therewith including the cylindrical outer bearing surface of the trunions.

Description

106~716 UNIVERSAL JOINT AND CROSS THEREFOR

Background of the Invention Field of the Invention. This invention relates generally to universal couplings and more particularly to universal joints and universal joint crosses.
Description of the Prior Art. The prior art is replete with various forms and types of universal couplings in which internal passages have been provided for lubrication of their various operational parts. Additionally, such prior art universal joints have included additional mechanisms and devices which attempt to improve the lubrication effectiveness. For example, United States Patent 3,070, 980 to Slaght, patented January 1, 1963, is representative of the prior art providing for an extremely complex bearing cap to enhance the lubricant flow to the needle bearings. United States Patent 3,006,168 to Kayser, patented October 31, 1961, also discloses a highly complex and expensive to manufacture self-lubricating universal joint having a multiplicity of parts which may fail during operation. United States Patent 3,353,374 to Buthenhoff, patented November 21, 1967, discloses a further example of a highly complex universal joint utilizing a plurality of moving seal and spring loaded devices. United States Patent 3,470,711 to Kayser, patented October 7, 1969, discloses yet another example of a highly complex universal joint and, more particularly, a cross therefor including a number of resilient members which may tend to distort and malfunction during operation. Other examples of 2û representative prior art which attempted to solve the lubrication problem are as follows:
United States Patent Number Patentee Patented 1,889,470 F. A. Garrett November 29, 1932 1,968,787 W. W. Slaght et al July 31, 1934 1,992,257 H. F. Braun et al March 5, 1935

2.025.502 W. B. Fageol December 24, 1934 2,081,505 J. E. Padgett May 25, 1937

3,087,314 V.E.Jarvisetal April3û, 1963 3,178,907 J. M. Lyons Apri 1 20, 1965 3,242,695 P. M. Ross, Jr. March 29, 1966 3,352,127 R. L. Skinner, Sr. November 14, 1967 3,611,751 Hans-Joachim Kleinschmidt October 12, 1971 3,721,11 û Borneman March 2û, 1973 3,832,865 Lewis September 3, 1974 The above-noted voluminous prior art patents all may be generally characterized as highly complex and generally vulnerable to malfunction and expensive to manufacture and none of such prior art devices includes effective means to ensure that each of the 3~

~069716 critical bearing areas are lubricated during each lubricating cycle. Further, they may be additionally characterized as difficult to maintain in the field, thus, potentially resulting in substantial downtime of the vehicle with which they are operationally associated.
Summary of the Invention According to one aspect of the present invention there is provided a universal joint including a cross operably connected therein, said cross comprising a body having four trunnions extending therefrom along two mutually perpendicular lines, a lubrication network in said body and said trunnions to provide lubrication to the cylindrical outer bearing surface of said trunnions, said network including a plurality of branches in communication with each other and terminating in a counterbore provided internally in each of said trunnions, each said counterbore having a cylindrical inner surface coaxial with said cylindrical outer bearing surface of said trunnions, said counter-bore being open at its end opposite said branches, a flow metering member having at least one metering orifice therethrough fixedly disposed within each of said counterbores to meter lubricant flowing through each of said branches downstream into said counterbore and to the bearing means in bearing engagement with the cylindrical outer bearing surface of said trunnions, said filtering means being a screen provided upstream of each of said metering orifices to filter particulate matter from said lubricant to avoid clogging of said metering orifice and to ensure the free flow of said lubricant through said orifice, there being a radially extending surface at the junction of each branch and said counterbore, said metering orifice member being a substantial-ly rigid member and is held fixedly in place within said counterbore near said radially extending shoulder by interference fit between its outer surface and said inner cylindrical surface of said counterbore.
According to another aspect of the present invention there is pro-vided a cross for a universal joint comprising a body having four trunnions extending therefrom along two mutually perpendicular lines~ a lubrication 106971~

network in said body and said trunnions to provide lubrication to the cylindrical outer bearing surface of said trunnions, said network including a branch in each of said trunnions, each of said branches in communication with each other and each terminating in a counterbore provided internally and at an extended end of each of said trunnions, each said counterbore having a cylindrical inner surface coaxial with said cylindrical outer bear-ing surface of said trunnions, said counterbore being open at its end opposite said branches, a flow metering member having at least one metering orifice therethrough fixedly disposed within each of said counterbores to meter lubricant flowing from each of said branches downstream into said counterbore and to the bearing means in bearing engagement with the cylindrical outer bearing surface of said trunnion, a filtering means includes a screen provided upstream of each of said metering orifices to filter particulate matter from the lubricant to avoid clogging of said metering orifice and to ensure the free flow of said lubricant through said orifice, a diffusion baffle plate having a plurality of apertures therein is fixedly disposed in each counter-bore downstream of and near said metering orifice member to provide a uniform flow of said lubricant to said bearing means and to avoid the generation of any air pockets within the lubricant flowing to said bearing means.

~0~;S`716 Description of the Drawings The accompanying drawings referred to herein and constitute a part hereof illustrate the embodiments of the invention and together with the description serve to explain the principle of the invention wherein:
Figure I shows a universal joint in elevation partially in phantom with the several operational parts of one of the trunions in an exploded view with certain parts thereof in section; Figure I also shows the top trunion in a sectional view;
Figure 2 is a side elevational view of the universal joint of Figure l;
Figure 3 is the universal joint cross of the universal joint of Figure I partially in I O section;
Figure 4 is the cylindrical insertable plastic member to be inserted in a counterbore in each of the trunions of the universal joint of Figure l;
Figure 5 is the metering member which constitutes a part of the insertable plastic member of Figure 4;
Figure 6 is a thrust washer used in the universal joint of Figure l; and Figure 7 is a partial sectional view of a trunion showing another general form of the invention.

Description of the Preferred Embodiments Referring now to the drawings and particularly Figures 1-6, there is shown a 2û universal joint 10 employing the concept of the present invention. For the purposes of the description of the present invention, the word "axial" shall be used in reference to the axis of rotation of the universal joint connecting the drive shaft members with which it is operably associated and the word "radial" shall mean the direction extending perpendicular relative to the above-mentioned axis of rotation. Unless otherwise mentioned, the words "radial" and "axial" shall be used and construed in the above manner. The universal joint 10 comprises a number of parts and the basic element of the various parts is the universal joint cross 12. As the name implies, the universal joint cross or cross having two intersecting and perpendicular arms have trunions 14 at each end thereof. The cross of journal cross 12 has a cylindrical bearing raceway surface 16 formed thereon. The bearing 30 surface 16 will be explained in greater detail below.
The journal cross 12 is provided with a lubrication network including a central lubrication area 18. The lubricant, which is typically a high grade lubricant grease, is introduced into the lubrication area by means of grease fitting 2û which is in communication with an intermediate channel 11 which, in turn, is in communication with the central area 18. The grease fitting 20 is provided with a protective cap 24 which maintains the cleanliness of the grease fitting from its hostile environment encountered during operation of the universal joint 10. The central area 18 is provided with a series of branches and, more specifically, with four branches 26 which direct the lubricant toward each of the trunions 14. Each of the branches 26 terminate in a counterbore 28 which is provided internally in each of the trunions 14. The internal counterbores 28 are provided iO with a cylindrical inner surface 3û coaxial with the cylindrical outer bearing surface 16.
A generally radially extending shoulder or surface 32 is provided at the junction of each of the branches 26 and the counterbore 28. The generally radially extending shoulder 32 may be formed in a truncated conical fashion and the purpose of the shoulder 32 will be more fully explained below.
The cross 12 may be characterized, therefore, as a simplistic and rugged structure which is highly adaptable to state-of-the-art forging, machining and grinding techniques. The cross 12 may be manufactured from a range of suitable material as, for example, 8620 steel and may be heat treated after machining and forming typically in a high carbon atmosphere to increase its strength and enhance the lubricity of the bearing surface 16.
The counterbore 28 in each of the trunions 14 is adapted to receive several parts for performing a number of different functions, which functions relate to the filtration, metering, diffusing and ultimate effective delivery of the lubricant to the various critical wear areas of the universal joint lû. As before mentioned, there is provided a generally radial Iy extending shoulder or surface 32 at the junction of the counterbore 28 and each of the branches 26. This frustoconical section acts as a seat for a filtering member or screen 34 which may be shaped in a substantially and complementary conical form. The filtering screen 34 may be generally pressed into place to abut and be seated upon the radially extending surface 32. The filtering screen 34 is held in its operational position by the insertion of a generally cylindrical, substantially rigid cylindrical member 36, i.e., the cylindrical member 36 captures the filtering screen 34 between the radial shoulder 32 and itself. The filtering screen 34 may be manufactured from a wide range of galvanized or 10697~6 stainless steel and has a mesh of approximately .022 of an inch. The cylindrical member 36 in its inserted position, as shown in Figure 3, is in a generally interference fit with the inner cylindrical surface 30 of the counterbore 28. For example, the outer diameter of the cylindrical member 36 may be approximately .002 of an inch greater than the inner diameter of the counterbore. The cylindrical member 36 and its various component parts are of critical importance in understanding the present invention and comprise a real and substantial advantage over the prior art as typified by the prior art referred to in the Background of the Invention. The cylindrical member 36 may be manufactured from a plastic material, 6/6 nylon as manufactured by DuPont, and may have such a wall DO~
3~ thickness as to allow for its insertion with ai~ inch interference fit. The cylindrical member 36 is provided with a f low metering member 38.
The metering member 38 or plate is provided with a centrally disposed metering orifice 40 therethrough which meters the lubricant as it leaves the various branches 26, flows through and is filtered by the filtering screen 34 and encounters the metering plate 38. In a typical application the orifice 40 may be approximately .032 of an inch in diameter. The metering member or plate 38 may be formed integrally with the cylindrical member 36 or otherwise suitably attached or connected thereto as by a pressfit therein.
Obviously, mounting techniques and other economics enter into the specific method and form in which the metering plate 38 is interfitted with the cylindrical member 36.
As the lubricant encounters and is metered by the metering member 38 and flows through the orifice 40 thereof it then encounters a diffusion baffle plate 42. The baffle plate 42 is provided with a plurality of apertures or openings 44 which act to diffuse the lubricant as it flows through the baffle plate 42. It has been found that the action of the baffle plate and, more particularly, the various apertures 44 reduce and substantially eliminate "air locks" or entrapped air within the lubricant stream; thus enhancing the consistency and continuity of flow of the lubricant to the various critical wear areas. As with the metering plate 38, the baffle plate 42 may be formed integrally with or otherwise fixedly attached to the cylindrical member 36. As shown in Figure 4, the baffle plate 42 is shown formed integrally with the cylindrical member 36 while the metering member is shown pressfitted therein and thereto. The apertures 44 may typically be in a range from .040 to .050 of an inch. There may be provided in a typical application ten such apertures 44.

~069716 The cylindrical member 36 when in its fully inserted position within the counterbore 28 will not protrude beyond the radial extremity of the trunion but may terminate at or below the inner surface of the counterbore 28.
Each trunion 14 is adapted to receive several operational parts. The bearing cupor cap 46 is adapted to be fitted over each of the trunions 14. The cylindrical inner surface 48 of the bearing cap 46 and the outer cylindrical surface 16 of the trunions provide the bearing raceways for the full complement of needle bearings 5û. A resilient seal 52 surrounds and is mounted upon a shoulder 54 provided on each of the trunions 14.
A spacer piece 56 is provided between the resilient seal 52 and needle bearing 5û to maintain the rotational alignment of the needle bearings 50 as they encircle the bearing surface 16 of the trunions 14.
Another important element of the present invention is found in the thrust washer58 provided between the inner end 6û of the cap 46. The thrust washer 58 is best shown in its enlarged form in Figure 6. The thrust washer 58 is provided with a central bore aperture 62 and alternating offset portions 64 which are offset from the original plane of the washer 58. The thrust washer 58 performs a number of functions including themaintenance of the alignment of the needle bearings 50 in a manner similar to the spacer piece 56. Additionally, and more importantly, the thrust washer 58 acts as a thrust bearing between the bearing cap 46 and the journal cross 12, i.e., as a generally radial force is transmitted through the cap to the journal cross it is generally absorbed and mitigated by the thrust washer which is a compliant member. This compliance or resiliency is achieved by the alternating offset portions and by the selection of material as, for example, austempered spring steel. This shock absorbing feature of the thrust washer 58 increases the longevity of the overall universal joint lû and specifically reduces the galling or wear of the ends of the trunions 14. Each of the bearing caps 46 has a plate 66 attached to the tops thereof to secure them to their respective drive member yokes (not shown).
The yokes may be suitably threaded to receive the threaded bolts 68 which secure the plates 66 to the yokes. Thereafter, the bolts are locked in place by suitable locking means such as locking plates 70 having locking tangs 72 thereon.
It can be seen, therefore, that as the lubricant is introduced under pressure through the fitting 2û the pressure will force the lubricant to flow toward the trunions 14 ~069716 and the critical wear areas (e.g. bearing surfaces 16, 48 and 60, bearings 50, etc.) under pressure in the range of approximately 50û p.s.i. The flow of the lubricant will be from the central area 18 through the branches 26 to be then filtered by the filtering screen 34, metered by the metering member 38 and diffused by the baffle plate 42 and ultimately to the aforementioned critical wear areas in a consistent and effective rate therefrom. The thrust washer will enhance this flow by channeling the lubricant through the channels 74 intermediate the various alternating offset portions 64.
An additional important feature of the present invention is that once the pressurized introduction of lubricant ceases the lubricant will not flow back to the central lû area 18 from the trunions when the universal joint is in a stationary position. This is achieved essentially by the metering orifice 40 of the metering member or plate. The surface tension of the lubricant at the metering orifice is of such a magnitude as to overcome the force of the lubricant due to gravity even if one of the trunions stops in a vertical direction. The various apertures 44 of the baffle plate 42 also tend to inhibit the return of the lubricant to the central area 18. This is important for the various critical wear areas must be suitably lubricated as they begin to rotate or serious wear damage will occur.
Figure 7 shows another general form of the present invention in which the various parts are substantially the same as the above-noted structure except that the metering member 76 is a cup like member in which its outer cylindrical surface 28' is pressfitted within the counterbore in each of the trunions 14'. The metering member 76 is provided with a centrally disposed metering orifice 80 which acts in a fashion similar to the metering orifice 40 of the metering member 38. The metering member 76 may be manufactured of a suitable substantially rigid material such as stainless steel, nylon or the like.
Obviously, the present invention is not limited to the specific details as hereinabove described but is capable of other modifications and changes without departing from the spirit and the scope of the appended claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A universal joint including a cross operably connected therein, said cross comprising a body having four trunnions extending therefrom along two mutually perpendicular lines, a lubrication network in said body and said trunnions to provide lubrication to the cylindrical outer bearing surface of said trunnions, said network including a plurality of branches in communica-tion with each other and terminating in a counterbore provided internally in each of said trunnions, each said counterbore having a cylindrical inner surface coaxial with said cylindrical outer bearing surface of said trunnions, said counterbore being open at its end opposite said branches, a flow metering member having at least one metering orifice therethrough fixedly disposed within each of said counterbores to meter lubricant flowing through each of said branches downstream into said counterbore and to the bearing means in bearing engagement with the cylindrical outer bearing surface of said trun-nions, said filtering means being a screen provided upstream of each of said metering orifices to filter particulate matter from said lubricant to avoid clogging of said metering orifice and to ensure the free flow of said lubricant through said orifice, there being a radially extending surface at the junction of each branch and said counterbore, said metering orifice member being a sub-stantially rigid member and is held fixedly in place within said counterbore near said radially extending shoulder by interference fit between its outer surface and said inner cylindrical surface of said counterbore.

2. A universal joint including a cross operably connected therein as set forth in claim 1, wherein a diffusion baffle plate having a plurality of apertures therein is fixedly disposed in said each counterbore downstream of and near said metering orifice member to provide a uniform flow of said lubricant to said bearing means and to avoid the generation of any air pockets within said lubricant flowing to said bearing means.

3. A universal joint including a cross operably connected therein as set forth in claim 2, wherein there is one metering orifice in said metering member centrally disposed thereon and there are 10 apertures in said baffle plate.

4. A universal joint including a cross operably connected therein as set forth in claim 2, wherein said baffle plate is of substantially rigid plastic material pressfitted within said counterbore.

5. A universal joint including a cross operably connected therein as set forth in claim 4, wherein said metering member and said baffle plate are nylon and each said baffle plate and said metering orifice member are carried by a cylindrical plastic member the outer cylindrical surface of which is in interference fit relation with the inner cylindrical surface of said counter-bore.

6. A universal joint including a cross operably connected therein as set forth in claim 5, wherein said baffle plate is formed integrally with said cylindrical plastic member which is of nylon.

7. A universal joint including a cross operably connected therein as set forth in claim 6, wherein said metering member is pressfitted with the inner surface of the nylon cylindrical member.

8. A universal joint including a cross operably connected therein as set forth in claim 1, wherein said metering member is a steel cupped shaped member whose annular lip is in interference fit relation with the inner surface of said counterbore.

9. A universal joint including a cross operably connected therein as set forth in claim 2, wherein there is a substantially small space between the downstream side of said metering member and the upstream side of said baffle plate.

10. A cross for a universal joint comprising a body having four trun-nions extending therefrom along two mutually perpendicular lines, a lubrica-tion network in said body and said trunnions to provide lubrication to the cylindrical outer bearing surface of said trunnions, said network including a branch in each of said trunnions, each of said branches in communication with each other and each terminating in a counterbore provided internally and at an extended end of each of said trunnions, each said counterbore having a cylindrical inner surface coaxial with said cylindrical outer bearing surface of said trunnions, said counterbore being open at its end opposite said branches, a flow metering member having at least one metering orifice there-through fixedly disposed within each of said counterbores to meter lubricant flowing from each of said branches downstream into said counterbore and to the bearing means in bearing engagement with the cylindrical outer bearing surface of said trunnion, a filtering means includes a screen provided up-stream of each of said metering orifices to filter particulate matter from the lubricant to avoid clogging of said metering orifice and to ensure the free flow of said lubricant through said orifice, a diffusion baffle plate having a plurality of apertures therein is fixedly disposed in each counter-bore downstream of and near said metering orifice member to provide a uniform flow of said lubricant to said bearing means and to avoid the generation of any air pockets within the lubricant flowing to said bearing means.